This invention relates to an amide derivative represented by the following general formula (I) ##STR2## wherein one of X and Y represents a sulfur atom and the other represents a carbon atom, Z represents a nitrile or thioamide group, each of R.sup.1 and R.sup.2 represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, a halomethyl group or a phenyl group, and R.sup.3 represents an alkenyl group having 2 to 6 carbon atoms, a haloalkenyl group having 2 to 4 carbon atoms, a furyl group, a thienyl group, an alkoxy group having 1 to 4 carbon atoms, an alkylthio group having 1 to 4 carbon atoms, an alkynyloxy group having 3 to 5 carbon atoms, an alkynylthio group having 3 to 5 carbon atoms, a pyrazolyl group, or an unsubstituted or halo-substituted phenyl group; processes for producing the amide derivative; an agricultural-horticultural fungicide comprising the amide derivative as an active ingredient; and to an agricultural-horticultural fungicidal composition comprising the amide derivative of general formula (I) as a first active ingredient and at least one member selected from the group consisting of acylalanine fungicides having the action of controlling plant diseases caused by Oomycetes, dithiocarbamate fungicides, N-haloalkylthioimide fungicides, inorganic copper fungicides, tetrachloroisophthalonitrile, dichlofluanide and fluazinam.
Heretofore, compounds having various chemical structures have been used as agricultural-horticultural fungicides, and greatly contributed to the control of plant diseases and consequently to the development of agriculture. But these conventional fungicidal chemicals have not proved to have sufficient controlling activity and safety. For example, some of dithiocarbamate fungicides such as zinc ethylenebis(dithiocarbamate) [zineb], manganese ethylenebis(dithiocarbamate) [maneb], a complex of manganese ethylenebis(dithiocarbamate) and zinc ethylenebis(dithiocarbamate [mancozeb] and dizinc bis(dimethyldithiocarbamate) ethylenebis(dithiocarbamate) [polycarbamate], N-haloalkyl thioimide fungicides such as N-trichloromethylthio-4-cyclohexene-1,2-dicarboximide [captan], N-1',1',2',2'-tetrachloroethylthio-4-cyclohexene-1,2-dicarboximide [captafol] and N-trichloromethylthiophthalimide [folpet], inorganic copper fungicides such as cupric sulfate, basic cupric sulfate, basic cupric chloride and cupric hydroxide, tetrachloroisophthalonitrile [TPN], N-(dichlorofluoromethylthio)-N',N-dimethyl-N-phenylsulfamide[dichlofluanid e] and 3-chloro-N-(3-chloro-5-trifluoromethyl-2-pyridyl)-2,6-dinitro-4-trifluorom ethylaniline [fluazinam] show an outstanding control efficacy on diseases of plants such as fruit trees and vegetables and are widely used as agricultural-horticultural fungicides. However, these chemicals mainly exhibit a preventive effect and are not expected to produce a curative effect. Hence, they have the serious defect that when a plant disease is seen to occur, these chemicals are not expected to give a sufficient efficacy. When chemical application for controlling plant diseases is considered in an actual situation, the chemicals are more or less sprayed after the occurrence of plant disease symptoms, and the above-cited chemicals are difficult of controlling the diseases completely. Furthermore, the concentrations of these chemicals at which they exhibit a control effect are very high so that they are difficult to use safely, and some of these chemicals have an unnegligible toxicity to fish.
In order to eliminate these defects, extensive research work has been done on new controlling agents. For example, acylalanine fungicides, such as N-(2,6-dimethylphenyl)-N-(2'-methoxyacetyl)alanine methyl ester [metalaxyl], N-(2,6-dimethylphenyl)-N-(2-furoyl)alanine methyl ester [furalaxyl], N-(2,6-dimethylphenyl)-N-(phenylacetyl)alanine methyl ester [benalaxyl], (2-chloroacetamide [ofurace] and 2-methoxy-N-(2,6-dimethylphenyl)-N-(2-oxo-1,3-oxazolidin-3-yl)acetamide [oxadixyl] were developed as controlling agents on plant diseases caused by Oomycetes which also have an excellent curative effect have been developed and come into practical use worldwide. It has already been pointed out that resistant strain to these chemicals have appeared and their control effect have consequently decreased.
Many active benzylamide compounds have been discovered and used as herbicides or fungicides. For example, known substituted benzamide derivatives include ethyl N-benzoyl-N-(3,4-dichlorophenyl)-2-aminopropionate [benzoylprop ethyl] as herbicide, and N-(3-isopropoxyphenyl)-2-methylbenzamide [mepronil] as fungicide.
BP-2094786, BP-2095237, and BP-2107308 disclose a herbicide and a fungicide comprising a substituted benzylamide derivative having a 4-pyridylcarbonyl, 2-furylcarbonyl, 2-thienylcarbonyl or 2-benzofurylcarbonyl group, but its phytotoxicity on crop plants is a problem.
It is an object of this invention to provide a compound being free from the above-mentioned defects of the prior art and having excellent properties as an agricultural-horticultural fungicide; processes for production thereof, and an agricultural-horticultural fungicide comprising the compound as an active ingredient, and an agricultural-horticultural fungicidal composition comprising the compound as a first active ingredient and a specific known fungicidal compound as a second active ingredient. More specifically, the invention provides a compound which has a preventive and a curative effect on a wide range of plant diseases such as diseases of fruit trees and vegetables, shows an excellent control effect against resistant fungi, has a wide range of applicability and a long residual effect, does not show phytotoxicity on crop plants, and possesses very low toxicity on warm-blooded animals and fish; simple processes for production thereof in high yields; an agricultural-horticultural fungicide comprising the compound as an active ingredient; and an agricultural-horticultural fungicidal composition comprising the compound as a first ingredient and a specific known fungicidal compound as a second active ingredient.
We worked extensively on acylamide derivatives in order to achieve the above object, and have found that amide derivatives having a thiazole or isothiazole ring have biological activity which cannot at all be anticipated from the above-exemplified compounds and an excellent controlling effect on a wide range of plant diseases; and that particularly, these amide derivatives have both a preventive and a curative effect in controlling various crop diseases such as late blight and downy mildew.